Bright Night

In 2012, astronauts from the European Space Agency installed an experimental camera on the International Space Station (ISS). NightPod adjusts for the movement of the ISS relative to Earth, taking clear shots of entire cities at night – like Milan, here. Like many cities, LED lights (white) are spreading out to replace traditional halogen lighting (yellow). LEDs are more efficient, so the swap should reduce worldwide energy consumption. Yet researchers believe LEDs are being left on for longer – the ‘radiance’ of the Earth’s surface is increasing, not decreasing. Piercing blue light, which makes LEDs glow white, surrounds some cities 24 hours a day. In addition to confusing wildfire and annoying stargazers, relentless light can disrupt the human circadian rhythm, increasing the risk of diseases like breast cancer. Researchers hope that future NightPod images will show signs of people remembering to switch off at the end of the day.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

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• Image from NASA and the European Space Agency
• Research from GFZ German Research Centre for Geosciences, Potsdam, Germany
• Image originally published under a Creative Commons Licence (BY-NC 4.0)
• Published in Science Advances, November 2017